De novo membranous nephropathy in renal allografts with unusual histology.

To the Editor.--Gough et al (1) observed immunoglobulin M (IgM)-positive mesangial immune deposits in 9 of the 118 renal allograft biopsies. The authors also mention that, to the best of their knowledge, this entity (IgM-positive mesangial immune deposits) was not reported previously. My colleagues and I have reported 2 cases of de novo membranous nephropathy in renal allografts with unusual histology. (2) In one of those cases, immunofluorescence on a kidney transplant biopsy specimen showed diffuse mesangium IgM deposits. Initially, this case report was submitted for consideration for publication in a nephrology journal. The reviewers of that journal surmised that the immunoglobulin deposition was a result of nonspecific trapping; therefore, the manuscript was not accepted for publication.

Subsequently, we have seen several cases of IgM nephropathy in renal transplant recipients; at least 2 of them who were treated responded favorably to cyclophosphamide therapy. We are in the process of submitting a manuscript on those 2 cases.

(1.) Gough J, Yilmaz A, Yilmaz S, Benediktsson H. Recurrent and de novo glomerular immunecomplex deposits in renal transplant biopsies. Arch Pathol Lab Med. 2005;129:231-233.

(2.) Lal SM, Luger AM, Saha LK, Ross G Jr. De novo membranous nephropathy in renal allografts with unusual histology. Int J Artif Organs. 1995;18:78-80.

SUNDER M. LAL, MD

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The author has no relevant financial interest in the products or companies described in this article.